Rabbit Anti-Human SRF (C-terminal) Polyclonal antibody

We previously found that surface topographies induce the expression of the Scxa gene, encoding Scleraxis in tenocytes. Because Scxa is a TGF-beta responsive gene, we investigated the link between mechanotransduction and TGF-beta signaling. We discovered that mesenchymal stem cells exposed to both micro-topographies and TGF-beta 2 display synergistic induction of SMAD phosphorylation and transcription of the TGF-beta target genes SCX, alpha-SMA, and SOX9. Pharmacological perturbations revealed that Rho/ROCK/SRF signaling is required for this synergistic response. We further found an activation of the early response genes SRF and EGR1 during the early adaptation phase on micro-topographies, which coincided with higher expression of the TGF-beta type II receptor gene. Of interest, PKC activators Prostratin and Ingenol-3, known for inducing actin reorganization and activation of serum response elements, were able to mimic the topography-induced TGF-beta response. These findings provide novel insights into the convergence of mechanobiology and TGF-beta signaling, which can lead to improved culture protocols and therapeutic applications.

A detailed study of the near-surface structure and composition of Nb, the material of choice for superconducting radio-frequency accelerator (SRF) cavities, is of great importance in order to understand the effects of different treatments applied during cavity production. By means of surface-sensitive techniques such as grazing incidence diffuse x-ray scattering, x-ray reflectivity, and x-ray photoelectron spectroscopy, single-crystalline Nb(100) samples were investigated in and ex situ during annealing in an ultrahigh vacuum as well as in nitrogen atmospheres with temperatures and pressures similar to the ones employed in real Nb cavity treatments. Annealing of Nb specimens up to 800 degrees C in a vacuum promotes a partial reduction of the natural surface oxides (Nb2O5, NbO2, and NbO) into NbO. Upon cooling to 120 degrees C, no evidence of nitrogen-rich layers was detected after nitrogen exposure times of up to 48 h. An oxygen enrichment below the Nb-oxide interface and posterior diffusion of oxygen species towards the Nb matrix, along with a partial reduction of the natural surface oxides, was observed upon a stepwise annealing up to 250 degrees C. Nitrogen introduction to the system at 250 degrees C promotes neither N diffusion into the Nb matrix nor the formation of new surface layers. Upon further heating to 500 degrees C in a nitrogen atmosphere, the growth of a new subsurface NbxNy layer was detected. These results shed light on the composition of the near-surface region of Nb after low-temperature nitrogen treatments, which are reported to lead to a performance enhancement of SRF cavities.